Parallel ISCreateGeneral()

[Tim Stitt]

Matt,

It is in setup for MatLUFactorSymbolic() and MatLUFactorNumeric() calls 
which require index sets. I have distributed my rows across the 
processes and now just a bit confused about the arguments to the 
ISCreateGeneral() routine to set up the IS sets used by the Factor 
routines in parallel.

So my basic question is what in general is the length and integers that 
get passed to ISCreateGeneral() when doing this type of calculation in 
parallel? Are they local index values (0..#rows on process-1) or do they 
refer to the distributed indices of the global matrix?

Tim.

Matthew Knepley wrote:
> On Nov 18, 2007 11:34 AM, Tim Stitt <timothy.stitt at ichec.ie> wrote:
>   
>> OK..so I should be using the aggregate length returned by
>> MatGetOwnershipRange() routine?
>>     
>
> If you are using it to permute a Mat, yes.
>
>   Matt
>
>   
>> Thanks Matt for you help.
>>
>>
>> Matthew Knepley wrote:
>>     
>>> IS are not really parallel, so all the lengths, etc. only refer to local things.
>>>
>>>   Matt
>>>
>>> On Nov 18, 2007 11:22 AM, Tim Stitt <timothy.stitt at ichec.ie> wrote:
>>>
>>>       
>>>> Hi all,
>>>>
>>>> Just wanted to know if the "the length of the index set" for a call to
>>>> ISCreateGeneral() in a parallel code, is a global length, or the length
>>>> of the local elements on each process?
>>>>
>>>> Thanks,
>>>>
>>>> Tim.
>>>>
>>>> --
>>>> Dr. Timothy Stitt <timothy_dot_stitt_at_ichec.ie>
>>>> HPC Application Consultant - ICHEC (www.ichec.ie)
>>>>
>>>> Dublin Institute for Advanced Studies
>>>> 5 Merrion Square - Dublin 2 - Ireland
>>>>
>>>> +353-1-6621333 (tel) / +353-1-6621477 (fax)
>>>>
>>>>
>>>>
>>>>         
>>>
>>>
>>>       
>> --
>> Dr. Timothy Stitt <timothy_dot_stitt_at_ichec.ie>
>> HPC Application Consultant - ICHEC (www.ichec.ie)
>>
>> Dublin Institute for Advanced Studies
>> 5 Merrion Square - Dublin 2 - Ireland
>>
>> +353-1-6621333 (tel) / +353-1-6621477 (fax)
>>
>>
>>     
>
>
>
>   


-- 
Dr. Timothy Stitt <timothy_dot_stitt_at_ichec.ie>
HPC Application Consultant - ICHEC (www.ichec.ie)

Dublin Institute for Advanced Studies
5 Merrion Square - Dublin 2 - Ireland

+353-1-6621333 (tel) / +353-1-6621477 (fax)